“It’s the combined taxidermist and veterinarian approach: either way you get your dog back,” says David Himmelstein, an internist at the Harvard Medical School and co-author of a letter published in this week’s issue of the New England Journal of Medicine.

The largest tobacco investor on the list, the 160-year old Prudential company with branches in the US and the UK, has more than $1.5 billion invested in tobacco stocks. The runner-up was Toronto-based Sun Life Financial, which apparently holds over $1 billion in Philip Morris (Altria) and other tobacco stocks. In total, seven companies that sell life, health, disability, or long-term care insurance, have major holdings in tobacco stock.

Sun Life disputed the findings, but, as The Consumerist points out, the study raises some interesting questions about how much we can trust private insurers as we begin the health care reform debate.

Why are companies that claim to be concerned with the health of Americans investing in companies whose products undermine that health? Do insurance companies that own tobacco stocks have a vested interest in promoting smoking, rather than discouraging it?